Invalid Problem

You’ve spent time creating the perfect lab assignment for your students. You’ve tested it and it works perfectly. Now you’re ready for your students to give it a shot.

But instead of your beautiful lab assignment your students are getting an invalid problem error message.

What happened?

Below you’ll find a few reasons why your students might be seeing this error page, along with a few that would cause you to see it as well.

And if you’d rather have the tl;dr version, if it’s not working for your students the problem is probably saved as a draft.


Draft Problem Checkbox
Draft setting on a problem

If you can see a problem you’ve created for your students, but your students cannot, the first thing to check is to make sure the problem is published. As the author of a problem you’re able to see it when it’s in a draft state, but no one else can.

On the screen where you edit your problem there is a small slider right above the Save Problem button. Make sure that it says Published and not Draft. If it’s draft, switch it to published and save the problem. Your students should be able to see the problem now.

Permissions & Sharing

When you create a problem in ClassCube you are able to set who else can see and use the problem. There’s more information in the documentation on creating problems, but here’s the short version.

Private: You can create problems for your students. Your student can attempt the problems only if you create an assignment.

My Students: You can create problems for your students. Your students can attempt these problems even if you don’t create an assignment. These will typically be used for practice problems that you don’t plan on grading.

Shared Assignments: Similar to private, except any teacher that you are connected to can also use these problems. Their students will be able to attempt the problem if they have created an assignment.

Shared: Similar to my students except that any teacher you are sharing with, and their students, can attempt the problem whether an assignment is created or not.

Most common here would be one teacher creates an assignment and shares the link with another teacher. If the permissions are not correct on the problem or the teachers are not connected in ClassCube then the second teacher’s students will not be able to see the problem.

Maybe it’s actually invalid

Of course it’s also possible that the problem you’re linking to is actually invalid.

The most common cause is that a problem was deleted after the link was created. If that’s the case then you’ll need to recreate the problem, create an assignment for the new problem, and change the link to the new assignment.

It’s also possible that the link you or your students followed wasn’t correct. Your best bet is to copy the assignment link and paste it into where ever your students will be working rather than trying to type it in. Assignment links are not all that intuitive and typos come easily.

Still having problems

If you’re still having issues with problems not showing up please either start a thread in our support board or get in touch.